Loneliness in schizophrenia: Construct clarification, measurement, and clinical relevance

RESEARCH ARTICLE Loneliness in schizophrenia: Construct clarification, measurement, and clinical relevance Graham M. L. Eglit1,2, Barton W. Palmer1,2,3, A’verria S. Martin1,2, Xin Tu2, Dilip V. Jeste1,2,4* a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 Department of Psychiatry, University of California, San Diego, La Jolla, California, United States of America, 2 Sam and Rose Stein Institute for Research on Aging, University of California, San Diego, La Jolla, California, United States of America, 3 Veterans Affairs San Diego Healthcare System, San Diego, California, United States of America, 4 Department of Neuroscience, University of California, San Diego, La Jolla, California, United States of America * Abstract OPEN ACCESS Citation: Eglit GML, Palmer BW, Martin AS, Tu X, Jeste DV (2018) Loneliness in schizophrenia: Construct clarification, measurement, and clinical relevance. PLoS ONE 13(3): e0194021. https://doi. org/10.1371/journal.pone.0194021 Editor: Sinan Guloksuz, Department of Psychiatry and Neuropsychology, Maastricht University Medical Center, NETHERLANDS Received: November 2, 2017 Accepted: February 22, 2018 Published: March 22, 2018 Copyright: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This work was supported, in part, by National Institute of Mental Health (NIMH) grant 5R01 MH094151-04 (Jeste), the National Institute of Mental Health T32 Geriatric Mental Health Program MH019934 (PI: Jeste), and University of California San Diego’s Stein Institute for Research on Aging (Director: Jeste). The funders had no role in study design, data collection and analysis, Loneliness is a highly prevalent experience in schizophrenia. Theoretical models developed in the general population propose that loneliness is tantamount to a feeling of being unsafe, is accompanied by enhanced environmental threat perception, and leads to poor physical, emotional, and cognitive functioning. Previous research has reported that loneliness is associated with poorer physical and emotional health in schizophrenia; however, few studies have directly compared loneliness and its correlates in persons with schizophrenia and non-psychiatric comparison subjects. The purpose of the current study was to evaluate similarities and differences in the construct of loneliness, the equivalency of the measurement of this construct, and similarities and differences in the pattern of external correlates of loneliness between schizophrenia and non-psychiatric comparison groups. The third version of the University of California, Los Angeles Loneliness Scale (UCLA-3) was administered to 116 individuals with schizophrenia or schizoaffective disorder and 106 non-psychiatric comparison subjects. Additional clinical and positive psychological measures were collected, as well as demographic characteristics of the two groups. Multiple groups confirmatory factor analysis revealed that the UCLA-3 was best characterized by a bifactor model in which all items loaded on a general loneliness dimension as well as one of two orthogonal method factors reflecting item wording in both groups. Furthermore, the UCLA-3 exhibited invariant measurement of these latent constructs across groups. Mean levels of loneliness were nearly a standard deviation higher in the schizophrenia group. Nonetheless, the overall pattern and strength of correlates were largely similar across groups, with loneliness being positively associated with depression, anxiety, and perceived stress, and negatively correlated with mental well-being, happiness, and resilience. Subtle differences in correlates of age, optimism, and satisfaction with life were found. Overall, loneliness appears to be distinct from other schizophrenia-related deficits and operates similarly across schizophrenia and NC groups, suggesting that theoretical models of loneliness developed in the general population may generalize to schizophrenia. PLOS ONE | https://doi.org/10.1371/journal.pone.0194021 March 22, 2018 1 / 20 Loneliness in schizophrenia: Construct clarification, measurement, and clinical relevance decision to publish, or preparation of the manuscript. Competing interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: Dilip V. Jeste has received funding from the National Institute Mental Health. He is currently receiving grant funding by National Institute of Mental Health (NIMH) grant 5R01 MH094151-04 (Jeste) and the National Institute of Mental Health T32 Geriatric Mental Health Program MH019934 (PI: Jeste). This does not alter our adherence to PLOS ONE policies on sharing data and materials. Introduction Loneliness is increasingly being recognized as an important contributor to health and wellness. Surveys have highlighted a near doubling of the prevalence of loneliness from 20% to 35% among U.S. adults over the past decade [1–3]. Loneliness has been identified as a major risk factor for a range of negative health outcomes, including heart disease, depression, anxiety, and Alzheimer’s disease [4]. Furthermore, recent research suggests that loneliness, among other behavior and mood changes, may represent one of the earliest symptoms of neurocognitive disorders associated with aging [5–7]. In recognition of the negative impact and growing prevalence of loneliness, the former US Surgeon General Murthy has advocated treating this “loneliness epidemic” as a major public health concern, whose impact is on par with that of cigarette smoking and obesity [2]. Individuals with serious mental illnesses, especially those with psychotic disorders, may be especially prone to loneliness. In particular, individuals with schizophrenia are subject to stigma [8] and have greater clinical (e.g., positive symptoms, negative symptoms, etc.) challenges. In addition, on average, individuals with schizophrenia experience greater socio-environmental (e.g., poverty, low rates of employment, low rates of marriage) difficulties [9, 10], and are objectively less integrated within their communities [11, 12], although their perceived sense of belonging within the community may not differ from individuals without schizophrenia living in the same community [13]. Recent surveys indicate that self-reported annual rates of loneliness among individuals with schizophrenia and other psychotic disorders (76 to 80%) are approximately 2.3 times higher than those in the general population (35%) [14, 15]. Highlighting its clinical importance, loneliness has been reported as a significant contributor to worse quality of life in schizophrenia [16, 17] and individuals with psychotic disorders (...truncated)